This invention relates to a trigger-type device for operating a pump of the axial displacement piston type against a bias spring in order to spray liquids out of a handheld container, said pump having a spray delivery head which is movable axially together with the piston and provided with a delivery conduit extending at an angle to the piston displacement line substantially in the same plane where the angular movement of the trigger lever occurs, said device comprising a base body for supporting said pump and the trigger lever and for connection to the container mouth end.
Trigger-type devices of the kind outlines above have been long known in the related art and are currently employed for spraying liquids through the pressure developed by the mechanical action of the trigger lever on the pump, instead of using a gas propellant loaded into the container together with the liquid to be sprayed.
Such known devices have failed, however, to receive widespread acceptance because, although beneficial from an environmental standpoint, due to mechanical parts entering their construction which are subjected to reiterate stresses, they are liable to wear rapidly, and this also on account of the materials used for their construction being in general low grades, in order to fill the demand for disposability that usually underlies the manufacture of devices of this kind.
In addition, the constructions of conventional devices disallow automated assembly procedures for their component parts which could be implemented in a cost-efficient and straightforward manner.
Lastly, a non-negligible drawback of conventional devices is that their component parts are designed to make up a device suiting a specific type of respective container or a narrow range of container designs, which obviously restricts their field of application.
A known device of the kind mentioned above is illustrated by U.S. Pat. No. 3,478,935, for example, As brought out therein, the trigger-type lever or handle of the device is unitary with a lever which converts the angular movement of the trigger-type lever into a straight-line axial displacement of the pump piston and has substantial length, being pivoted on the base body at a very remote location from the trigger-type lever or handle.
In use, large flexural stresses are obviously applied to the lever-trigger handle combination which require that high grade, and hence expensive, materials be employed if long operational life is sought for the device.
Furthermore, in view of the complex construction of its components parts, the device of the aforementioned U.S. patent is unsuitable for automated assembly procedures using simple operations to be all carried out, for instance, in parallel with one and the same direction.
Another example of a known device is illustrated by French Patent Publication No. 2 398 196 which, once again, exhibits the same drawbacks as the device of U.S. Pat. No. 3,478,935.
In addition, and especially from the example of French Publication No. 2 398 196, it may be seen that its component parts are designed to match a specific configuration of the container and cannot provide a structurally independent device adaptable to a range of differently shaped containers.